A Thousand Brains: A New Theory of Intelligence

Don’t read this book at bedtime. Not that it’s frightening. It won’t give you nightmares. But it is so exhilarating, so stimulating, it’ll turn your mind into a whirling maelstrom of excitingly provocative ideas—you’ll want to rush out and tell someone rather than go to sleep. It is a victim of this maelstrom who writes the foreword, and I expect it’ll show.

Charles Darwin was unusual among scientists in having the means to work outside universities and without government research grants. Jeff Hawkins might not relish being called the Silicon Valley equivalent of a gentleman scientist but—well, you get the parallel. Darwin’s powerful idea was too revolutionary to catch on when expressed as a brief article, and the Darwin-Wallace joint papers of 1858 were all but ignored. As Darwin himself said, the idea needed to be expressed at book length. Sure enough, it was his great book that shook Victorian foundations, a year later. Book-length treatment, too, is needed for Jeff Hawkins’s Thousand Brains Theory. And for his notion of reference frames—“The very act of thinking is a form of movement”—bull’s-eye! These two ideas are each profound enough to fill a book. But that’s not all.

T. H. Huxley famously said, on closing On the Origin of Species, “How extremely stupid of me not to have thought of that.” I’m not suggesting that brain scientists will necessarily say the same when they close this book. It is a book of many exciting ideas, rather than one huge idea like Darwin’s.

I suspect that not just T. H. Huxley but his three brilliant grandsons would have loved it: Andrew because he discovered how the nerve impulse works (Hodgkin and Huxley are the Watson and Crick of the nervous system); Aldous because of his visionary and poetic voyages to the mind’s furthest reaches; and Julian because he wrote this poem, extolling the brain’s capacity to construct a model of reality, a microcosm of the universe:

The world of things entered your infant mind

To populate that crystal cabinet.

Within its walls the strangest partners met,

And things turned thoughts did propagate their kind.

For, once within, corporeal fact could find

A spirit. Fact and you in mutual debt

Built there your little microcosm—which yet

Had hugest tasks to its small self assigned.

Dead men can live there, and converse with stars:

Equator speaks with pole, and night with day;

Spirit dissolves the world’s material bars—

A million isolations burn away.

The Universe can live and work and plan,

At last made God within the mind of man.

The brain sits in darkness, apprehending the outside world only through a hailstorm of Andrew Huxley’s nerve impulses. A nerve impulse from the eye is no different from one from the ear or the big toe. It’s where they end up in the brain that sorts them out. Jeff Hawkins is not the first scientist or philosopher to suggest that the reality we perceive is a constructed reality, a model, updated and informed by bulletins streaming in from the senses. But Hawkins is, I think, the first to give eloquent space to the idea that there is not one such model but thousands, one in each of the many neatly stacked columns that constitute the brain’s cortex. There are about 150,000 of these columns and they are the stars of the first section of the book, along with what he calls “frames of reference.” Hawkins’s thesis about both of these is provocative, and it’ll be interesting to see how it is received by other brain scientists: well, I suspect. Not the least fascinating of his ideas here is that the cortical columns, in their world-modeling activities, work semi-autonomously. What “we” perceive is a kind of democratic consensus from among them.

Democracy in the brain? Consensus, and even dispute? What an amazing idea. It is a major theme of the book. We human mammals are the victims of a recurrent dispute: a tussle between the old reptilian brain, which unconsciously runs the survival machine, and the mammalian neocortex sitting in a kind of driver’s seat atop it. This new mammalian brain—the cerebral cortex—thinks. It is the seat of consciousness. It is aware of past, present, and future, and it sends instructions to the old brain, which executes them.

The old brain, schooled by natural selection over millions of years when sugar was scarce and valuable for survival, says, “Cake. Want cake. Mmmm cake. Gimme.” The new brain, schooled by books and doctors over mere tens of years when sugar was over-plentiful, says, “No, no. Not cake. Mustn’t. Please don’t eat that cake.” Old brain says, “Pain, pain, horrible pain, stop the pain immediately.” New brain says, “No, no, bear the torture, don’t betray your country by surrendering to it. Loyalty to country and comrades comes before even your own life.”

The conflict between the old reptilian and the new mammalian brain furnishes the answer to such riddles as “Why does pain have to be so damn painful?” What, after all, is pain for? Pain is a proxy for death. It is a warning to the brain, “Don’t do that again: don’t tease a snake, pick up a hot ember, jump from a great height. This time it only hurt; next time it might kill you.” But now a designing engineer might say what we need here is the equivalent of a painless flag in the brain. When the flag shoots up, don’t repeat whatever you just did. But instead of the engineer’s easy and painless flag, what we actually get is pain—often excruciating, unbearable pain. Why? What’s wrong with the sensible flag?

The answer probably lies in the disputatious nature of the brain’s decision-making processes: the tussle between old brain and new brain. It being too easy for the new brain to overrule the vote of the old brain, the painless flag system wouldn’t work. Neither would torture.

The new brain would feel free to ignore my hypothetical flag and endure any number of bee stings or sprained ankles or torturers’ thumbscrews if, for some reason, it “wanted to.” The old brain, which really “cares” about surviving to pass on the genes, might “protest” in vain. Maybe natural selection, in the interests of survival, has ensured “victory” for the old brain by making pain so damn painful that the new brain cannot overrule it. As another example, if the old brain were “aware” of the betrayal of sex’s Darwinian purpose, the act of donning a condom would be unbearably painful.

Hawkins is on the side of the majority of informed scientists and philosophers who will have no truck with dualism: there is no ghost in the machine, no spooky soul so detached from hardware that it survives the hardware’s death, no Cartesian theatre (Dan Dennett’s term) where a colour screen displays a movie of the world to a watching self. Instead, Hawkins proposes multiple models of the world, constructed microcosms, informed and adjusted by the rain of nerve impulses pouring in from the senses. By the way, Hawkins doesn’t totally rule out the long-term future possibility of escaping death by uploading your brain to a computer, but he doesn’t think it would be much fun.

Among the more important of the brain’s models are models of the body itself, coping, as they must, with how the body’s own movement changes our perspective on the world outside the prison wall of the skull. And this is relevant to the major preoccupation of the middle section of the book, the intelligence of machines. Jeff Hawkins has great respect, as do I, for those smart people, friends of his and mine, who fear the approach of superintelligent machines to supersede us, subjugate us, or even dispose of us altogether. But Hawkins doesn’t fear them, partly because the faculties that make for mastery of chess or Go are not those that can cope with the complexity of the real world. Children who can’t play chess “know how liquids spill, balls roll, and dogs bark. They know how to use pencils, markers, paper, and glue. They know how to open books and that paper can rip.” And they have a self-image, a body image that emplaces them in the world of physical reality and allows them to navigate effortlessly through it.

It is not that Hawkins underestimates the power of artificial intelligence and the robots of the future. On the contrary. But he thinks most present-day research is going about it the wrong way. The right way, in his view, is to understand how the brain works and to borrow its ways but hugely speed them up.

And there is no reason to (indeed, please let’s not) borrow the ways of the old brain, its lusts and hungers, cravings and angers, feelings and fears, which can drive us along paths seen as harmful by the new brain. Harmful at least from the perspective that Hawkins and I, and almost certainly you, value. For he is very clear that our enlightened values must, and do, diverge sharply from the primary and primitive value of our selfish genes—the raw imperative to reproduce at all costs. Without an old brain, in his view (which I suspect may be controversial), there is no reason to expect an AI to harbour malevolent feelings toward us. By the same token, and also perhaps controversially, he doesn’t think switching off a conscious AI would be murder: Without an old brain, why would it feel fear or sadness? Why would it want to survive?

In the chapter “Genes Versus Knowledge,” we are left in no doubt about the disparity between the goals of old brain (serving selfish genes) and of the new brain (knowledge). It is the glory of the human cerebral cortex that it—unique among all animals and unprecedented in all geological time—has the power to defy the dictates of the selfish genes. We can enjoy sex without procreation. We can devote our lives to philosophy, mathematics, poetry, astrophysics, music, geology, or the warmth of human love, in defiance of the old brain’s genetic urging that these are a waste of time—time that “should” be spent fighting rivals and pursuing multiple sexual partners: “As I see it, we have a profound choice to make. It is a choice between favoring the old brain or favoring the new brain. More specifically, do we want our future to be driven by the processes that got us here, namely, natural selection, competition, and the drive of selfish genes? Or, do we want our future to be driven by intelligence and its desire to understand the world?”

I began by quoting T. H. Huxley’s endearingly humble remark on closing Darwin’s Origin. I’ll end with just one of Jeff Hawkins’s many fascinating ideas—he wraps it up in a mere couple of pages—which had me echoing Huxley. Feeling the need for a cosmic tombstone, something to let the galaxy know that we were once here and capable of announcing the fact, Hawkins notes that all civilisations are ephemeral. On the scale of universal time, the interval between a civilisation’s invention of electromagnetic communication and its extinction is like the flash of a firefly. The chance of any one flash coinciding with another is unhappily small. What we need, then—why I called it a tombstone—is a message that says not “We are here” but “We were once here.” And the tombstone must have cosmic-scale duration: not only must it be visible from parsecs away, it must last for millions if not billions of years, so that it is still proclaiming its message when other flashes of intellect intercept it long after our extinction. Broadcasting prime numbers or the digits of π won’t cut it. Not as a radio signal or a pulsed laser beam, anyway. They certainly proclaim biological intelligence, which is why they are the stock-in-trade of SETI (the search for extraterrestrial intelligence) and science fiction, but they are too brief, too in the present. So, what signal would last long enough and be detectable from a very great distance in any direction? This is where Hawkins provoked my inner Huxley.

It’s beyond us today, but in the future, before our firefly flash is spent, we could put into orbit around the Sun a series of satellites “that block a bit of the Sun’s light in a pattern that would not occur naturally. These orbiting Sun blockers would continue to orbit the Sun for millions of years, long after we are gone, and they could be detected from far away.” Even if the spacing of these umbral satellites is not literally a series of prime numbers, the message could be made unmistakable: “Intelligent Life Woz ’Ere.”

What I find rather pleasing—and I offer the vignette to Jeff Hawkins to thank him for the pleasure his brilliant book has given me—is that a cosmic message coded in the form of a pattern of intervals between spikes (or in his case anti-spikes, as his satellites dim the Sun) would be using the same kind of code as a neuron.

This is a book about how the brain works. It works the brain in a way that is nothing short of exhilarating.